Beyonce unflinchingly parses through fact and fiction about her high-profile pregnancy in "Life Is but a Dream," her new HBO documentary that debuts later this month. As Us Weekly revealed on Thursday, the 31-year-old opens up candidly in the film about the miscarriage she and husband Jay-Z endured before the successful January 2012 birth of daughter Blue Ivy.

The singer also puts to rest, once and for all, persistent speculation that she used a surrogate to carry Blue Ivy. Conspiracy theorists harshly claimed that Beyonce even sported a false baby bump in the nine months leading up to her baby's birth.

"To think that I would be that vain," the Grammy winner retorts in the film. "I respect mothers and women so much. To be able to experience bringing a child into this world, if you're lucky and fortunate enough to experience that, I would never ever take that for granted."

She says of carrying a child: "It's the most powerful thing you can do in your life -- and especially after losing a child, the pain and trauma from that just makes it mean that much more. ... A child, you don't play around with that."

Calling her miscarriage the "saddest thing I've ever been through," she says becoming a mother to Blue became a truly life-defining moment. "My baby was born out of a conflict in my life and that struggle had to be settled. I wouldn't have gone through the pain if I hadn't gone down the path," she surmises. "There's something so relieving about life taking over you like that. You're playing a part in a much bigger show, and that's what life is, it's the greatest show on Earth. ... I felt like God was giving me a chance to assist in a miracle."

Beyonce plays the Super Bowl halftime show in New Orleans this Sunday. Singing the National Anthem live Thursday at a press conference for the event, she also acknowledged that she used a prerecorded track while singing the same song. "I did not have time to rehearse with the orchestra. It was a live television show. ... Due to the weather, due to the delay, due to no proper sound check... I did not feel comfortable singing live."

Still, this Sunday, she "absolutely" will be singing live, she assured reporters.